Aarti Sarwal

Neuromuscular ultrasound for evaluation of the diaphragm

Neuromuscular clinicians are often asked to evaluate the diaphragm for diagnostic and prognostic purposes. Traditionally, this evaluation is accomplished through history, physical exam, fluoroscopic sniff test, nerve conduction studies, and electromyography (EMG). Nerve conduction studies and EMG in this setting are challenging, uncomfortable, and can cause serious complications, such as pneumothorax. Neuromuscular ultrasound has emerged as a non‐invasive technique that can be used in the structural and functional assessment of the diaphragm. In this study we review different techniques for assessing the diaphragm using neuromuscular ultrasound and the application of these techniques to enhance diagnosis and prognosis by neuromuscular clinicians. Muscle Nerve 47:319‐329, 2013

Standardized Rehabilitation and Hospital Length of Stay Among Patients With Acute Respiratory Failure: A Randomized Clinical Trial

IMPORTANCE Physical rehabilitation in the intensive care unit (ICU) may improve the outcomes of patients with acute respiratory failure. OBJECTIVE To compare standardized rehabilitation therapy (SRT) to usual ICU care in acute respiratory failure. DESIGN, SETTING, AND PARTICIPANTS Single-center, randomized clinical trial at Wake Forest Baptist Medical Center, North Carolina. Adult patients (mean age, 58 years; women, 55%) admitted to the ICU with acute respiratory failure requiring mechanical ventilation were randomized to SRT (n=150) or usual care (n=150) from October 2009 through May 2014 with 6-month follow-up. INTERVENTIONS Patients in the SRT group received daily therapy until hospital discharge, consisting of passive range of motion, physical therapy, and progressive resistance exercise. The usual care group received weekday physical therapy when ordered by the clinical team. For the SRT group, the median (interquartile range [IQR]) days of delivery of therapy were 8.0 (5.0-14.0) for passive range of motion, 5.0 (3.0-8.0) for physical therapy, and 3.0 (1.0-5.0) for progressive resistance exercise. The median days of delivery of physical therapy for the usual care group was 1.0 (IQR, 0.0-8.0). MAIN OUTCOMES AND MEASURES Both groups underwent assessor-blinded testing at ICU and hospital discharge and at 2, 4, and 6 months. The primary outcome was hospital length of stay (LOS). Secondary outcomes were ventilator days, ICU days, Short Physical Performance Battery (SPPB) score, 36-item Short-Form Health Surveys (SF-36) for physical and mental health and physical function scale score, Functional Performance Inventory (FPI) score, Mini-Mental State Examination (MMSE) score, and handgrip and handheld dynamometer strength. RESULTS Among 300 randomized patients, the median hospital LOS was 10 days (IQR, 6 to 17) for the SRT group and 10 days (IQR, 7 to 16) for the usual care group (median difference, 0 [95% CI, -1.5 to 3], P = .41). There was no difference in duration of ventilation or ICU care. There was no effect at 6 months for handgrip (difference, 2.0 kg [95% CI, -1.3 to 5.4], P = .23) and handheld dynamometer strength (difference, 0.4 lb [95% CI, -2.9 to 3.7], P = .82), SF-36 physical health score (difference, 3.4 [95% CI, -0.02 to 7.0], P = .05), SF-36 mental health score (difference, 2.4 [95% CI, -1.2 to 6.0], P = .19), or MMSE score (difference, 0.6 [95% CI, -0.2 to 1.4], P = .17). There were higher scores at 6 months in the SRT group for the SPPB score (difference, 1.1 [95% CI, 0.04 to 2.1, P = .04), SF-36 physical function scale score (difference, 12.2 [95% CI, 3.8 to 20.7], P = .001), and the FPI score (difference, 0.2 [95% CI, 0.04 to 0.4], P = .02). CONCLUSIONS AND RELEVANCE Among patients hospitalized with acute respiratory failure, SRT compared with usual care did not decrease hospital LOS. TRIAL REGISTRATION clinicaltrials.gov Identifier: NCT00976833.

Ultrasonography in the intensive care setting can be used to detect changes in the quality and quantity of muscle and is related to muscle strength and function

PURPOSE This study aimed to (1) document patterns of quadriceps muscle wasting in the first 10 days of admission and (2) determine the relationship between muscle ultrasonography and volitional measures. MATERIALS AND METHODS Twenty-two adults ventilated for more than 48 hours were included. Sequential quadriceps ultrasound images were obtained over the first 10 days and at awakening and intensive care unit (ICU) discharge. Muscle strength and function were assessed at awakening and ICU discharge. RESULTS A total of 416 images were analyzed. There was a 30% reduction in vastus intermedius (VI) thickness, rectus femoris (RF) thickness, and cross-sectional area within 10 days of admission. Muscle echogenicity scores increased for both RF and VI muscles by +12.7% and +25.5%, respectively (suggesting deterioration in muscle quality). There was a strong association between function and VI thickness (r = 0.82) and echogenicity (r = -0.77). There was a moderate association between function and RF cross-sectional area (r = 0.71). CONCLUSIONS Muscle wasting occurs rapidly in the ICU setting. Ultrasonography is a useful surrogate measure for identifying future impairment. Vastus intermedius may be an important muscle to monitor in the future because it demonstrated the greatest change in muscle quality and had the strongest relationship to volitional measures.

Quantitative neuromuscular ultrasound in the intensive care unit

Introduction: Intensive care unit acquired weakness (ICU‐AW) results from a complex mixture of nerve and muscle pathology, and early identification is challenging. This pilot study was designed to examine the ultrasonographic changes that occur in muscles during ICU hospitalization. Methods: Patients admitted to the ICU for acute respiratory failure were enrolled prospectively and underwent serial muscle ultrasound for thickness and gray‐scale assessment of the tibialis anterior, rectus femoris, abductor digiti minimi, biceps, and diaphragm muscles over 14 days. Results: Sixteen participants were enrolled. The tibialis anterior (P = 0.001) and rectus femoris (P = 0.041) had significant decreases in gray‐scale standard deviation when analyzed over 14 days. No muscles showed significant changes in thickness. Conclusions: Ultrasound is an informative technique for assessing muscles of patients in the ICU, and lower extremity muscles demonstrated increased homogeneity during ICU stays. This technique should be examined further for diagnosing and tracking those with ICU‐AW. Muscle Nerve, 2013

Interobserver Reliability of Quantitative Muscle Sonographic Analysis in the Critically Ill Population

There is growing interest in the use of quantitative high‐resolution neuromuscular sonography to evaluate skeletal muscles in patients with critical illness. There is currently considerable methodological variability in the measurement technique of quantitative muscle analysis. The reliability of muscle parameters using different measurement techniques and assessor expertise levels has not been examined in patients with critical illness. The primary objective of this study was to determine the interobserver reliability of quantitative sonographic measurement analyses (thickness and echogenicity) between assessors of different expertise levels and using different techniques for selecting the region of interest.

Radiological Correlate of Ocular Flutter in a Case with Paraneoplastic Encephalitis

We present an interesting [18F]fluoro‐2‐deoxyglucose positron emission tomography (FDG‐PET) imaging finding in a patient with ocular flutter and cerebellar ataxia as part of anti‐Ma 1/2 antibody‐mediated paraneoplastic syndrome associated with a testicular seminoma. He had a typical anterior mesial temporal hyperintensity on magnetic resonance imaging (MRI) without gadolinium enhancement. In addition, his FDG‐PET images showed increased deep cerebellar and inferior rectus and superior oblique ocular muscles FDG uptake. This case is the first to visualize in vivo the possible underlying neuropathological mechanism of ocular flutter associated with cerebellar nuclei on functional imaging.

Ultrasound assessment of the diaphragm: Preliminary study of a canine model of X-linked myotubular myopathy

Introduction: We tested the feasibility of using neuromuscular ultrasound for non‐invasive real‐time assessment of diaphragmatic structure and function in a canine model of X‐linked myotubular myopathy (XLMTM). Methods: Ultrasound images in 3 dogs [wild‐type (WT), n = 1; XLMTM untreated, n = 1; XLMTM post–AAV8‐mediated MTM1 gene replacement, n = 1] were analyzed for diaphragm thickness, change in thickness with respiration, muscle echogenicity, and diaphragm excursion amplitude during spontaneous breathing. Results: Quantitative parameters of diaphragm structure were different among the animals. WT diaphragm was thicker and less echogenic than the XLMTM control, whereas the diaphragm measurements of the MTM1‐treated XLMTM dog were comparable to those of the WT dog. Conclusions: This pilot study demonstrates the feasibility of using ultrasound for quantitative assessment of the diaphragm in a canine model. In the future, ultrasonography may replace invasive measures of diaphragm function in canine models and in humans for non‐invasive respiratory monitoring and evaluation of neuromuscular disease. Muscle Nerve 50: 607–609, 2014

Use of Ketamine in Barbiturate Coma for Status Epilepticus.

ObjectivesWe described the use of adjunctive ketamine to terminate seizure activity and decrease the dose and duration of pentobarbital coma in 2 patients with refractory status epilepticus (SE). CasesA 56-year-old woman (patient 1) developed SE after cardiac arrest, which was refractory to antiepileptic agents and escalating doses of continuous midazolam. Midazolam was replaced with pentobarbital infusion with no significant change in electroencephalography. A continuous ketamine infusion was initiated as an adjunct to pentobarbital. After initiation of ketamine, seizure frequency decreased and sustained burst suppression was achieved. After 48 hours of induced burst suppression, pentobarbital was discontinued followed by ketamine and the patient remained seizure on oral anticonvulsants alone. Meanwhile, a 57-year-old woman (patient 2) with autoimmune encephalitis developed SE, which was refractory to first-line medications. Pentobarbital infusion was initiated with attainment of burst suppression on electroencephalography. Multiple attempts at weaning pentobarbital failed because of recurrence of seizures. To minimize the dose of pentobarbital needed, a continuous ketamine infusion was initiated as an adjunct to pentobarbital with maintenance of burst suppression at much lower doses of pentobarbital than before. Ketamine was continued for 19 days with titration of other antiepileptic therapy, without return of SE. ConclusionsThese cases demonstrate that ketamine may show promise as an adjunct to induced pentobarbital coma for refractory SE. Adjunctive use of ketamine may reduce the dose and duration of pentobarbital required, hence preventing complications associated with barbiturate therapy. Future studies are needed to define the optimal dose, timing, and role of ketamine infusions in the management of refractory SE.

Hyponatremia and Voltage Gated Potassium Channel Antibody Associated Limbic Encephalitis

Limbic encephalitis may occur as an infectious, paraneoplastic, or autoimmune phenomenon. One such cause of limbic encephalitis is voltage gated potassium channel antibodies (VKGC). Hyponatremia with new cognitive decline may be one of the presenting symptoms. The exact mechanism of hyponatremia is unknown though findings consistent with syndrome of inappropriate antidiuretic hormone (SIADH) are observed. We retrospectively reviewed all cases admitted to an academic medical center with a diagnosis of limbic encephalitis (848 adults between 2004 to 2010) and found six cases of VGKC antibody associated limbic encephalitis. Three of the six cases had SIADH that completely or partially resolved with a combination of water restriction and immunotherapy. The reversibility of hyponatremia and limbic encephalitis with immunomodulation suggests an antibody-mediated cause. We further review available literature for association of hyponatremia and VGKC limbic encephalitis and propose mechanisms of for the hyponatremia in autoimmune encephalitis

Patient With Voltage-Gated Potassium-Channel (VGKC) Limbic Encephalitis Found to Have Creutzfeldt-Jakob Disease (CJD) at Autopsy

To the Editor: Key differential diagnoses of patients presenting with rapidly-progressive dementia include autoimmune encephalitis, such as antibodies to the voltage-gated potassium channel (VGKC), and Creutzfeldt-Jakob disease (CJD). Correct and timely diagnosis of the etiology is paramount, given the catastrophic progression of CJD and the potential for response to immunomodulatory therapy in autoimmune encephalitis. The antemortem diagnosis of rapidly-progressive dementia is predominantly clinical. For example, CJD has established diagnostic criteria that include clinical examination, characteristic findings on electroencephalography (EEG) and brain magnetic resonance imaging (MRI), and cerebrospinal fluid (CSF) 14–32 3. This is in contrast to VGKC limbic encephalitis, which does not have established diagnostic criteria. VGKC typically presents with confusion, seizures, psychosis, and hyponatremia. An underlying cancer has been identified in 47% of patients with VGKC. CJD has been previously promoted as being a mimic of VGKC limbic encephalitis. However, the significance of VGKC antibodies in patients with strong clinical, serologic, and/or imaging evidence of CJD is uncertain. We present a patient with rapidly-progressive dementia who was positive for the VGKC antibody, but with histopathological diagnosis of prion disease at autopsy.